Have you ever noticed how it's usually the smaller dogs that seem the most ferocious? That's what your mother meant when she told you never to judge a book by its cover.

And the endearing thing about good motherly advice is that it tends to apply to a broad range of subjects. It's why, for instance, you shouldn't make assumptions about the nature of a game based solely on its looks: Puyo Pop Fever's graphics may be simplistic, but their friendly colourful nature masks a complex and fiendish puzzle game.

We'll get to that in a minute, but first, the basics. Puyos are blobs that fall from the top of the screen in formations of two, three or four, and come in a quintet of hues. When four or more identically coloured puyos touch after coming to a rest, they gel and disappear. No prizes for guessing that the idea is to position puyo blocks as they descend (their formation can also be rotated) so as to get them to meet up with their appropriately tinted comrades already sat waiting at the bottom of the screen.

Do that for long enough and you're bound to lose every game you start.

Here's why: rather than patting yourself on the back for managing to match colours on a one-by-one basis while displaying the blissful ignorance you might expect from a two-year-old, what you really want to be doing is setting up situations for 'chains'.

Chains occur when clearing a group of puyos causes the rest of the field to crumble and, as it does, other groups of same colour puyos to come in contact and subsequently disappear, opening the way for a further chain. Like a chain reaction. The clue's in the terminology, really.

Setting up suitably intricate chains, however, requires Kasparov-levels of perception – at least initially. Like most things, play long enough and you begin to recognise and replicate certain set patterns almost subconsciously. Don't think autopilot will get you out of all situations, though: you'll need to maintain high brain activity if you plan to beat your opponent.

Did I not mention this is a battle? That's partially why chains are crucial, you see. Every time you eliminate a group of puyos, they appear on your adversary's playfield as 'nuisance' puyos – ghost-like grey blobs that can only be destroyed when you clear a normal puyo adjacent to them. So if you're regularly getting puyo chains, you should soon have the other player's screen filled with puyo waste. And once there's no room left for normal falling puyo formations, it's game over. You win.

Of course, the reverse is true too, but you can combat nuisance puyos by 'offsetting' them before they show up on your screen, which you do with chains or standard puyo grouping (though obviously the higher the number or bigger the chain, the better). Rather conveniently, offsetting also fills your Fever meter, which once topped up sends you into a selection of pre-filled screens offering a brief taste of puyo chain heaven, provided you place the falling formation in the right place. Play well and your opponent may not recover from the assault.

And that's Puyo Pop in 400-odd words. There's a variety of modes such as Mission and Fever, as well as a handful of rule options to enable you to customise your Puyo experience the way you wish (traditionalists who've played the game before, for instance, may want to switch off Fever mode, though we think it throws an interesting new dynamic into the mix). But beware, it's not enough to make this essential puzzling if you're only planning to play on your own.

Unlike, say, the magnificent Tetris, this is the kind of thing best enjoyed when battling another human, not least because some of the difficulty spikes when playing the PSP-controlled opponents can be shocking. So we're glad to report there's two-player wireless compatibility, as well as the option for two individuals to share a game (and their personal space) on one PSP.

If you haven't got any friends, there's still plenty to recommend; even the difficulty issue mentioned above can be bypassed by keeping off the main single-player mode and engaging instead in Free Battle or some of the other settings.

Puyo Pop Fever is an accomplished puzzle title whose affable looks and gameplay bite will no doubt attract interest. A bit like a pink ribboned Chihuahua with a Great White smile.